Psoriasis is a common chronic inflammatory skin disease. Diabetes is a group of metabolic diseases characterized by chronic hyperglycemia due to absolute or relative deficiencies in insulin secretion and insulin resistance. Current epidemiological studies indi－cate that patients with psoriasis have a significantly higher risk of developing diabetes than the general population. Patients with psoriasis have significantly higher levels of tumor necrosis factor-α（TNF-α） which plays an important role in insulin resistance. It has been found that four susceptible genes of psoriasis，CDKAL1，PSORS2，PSORS3 and PSORS4，are related to type 2 diabetes mellitus. In addition，our previous studies suggested that an hypoglycemicdrug，thiazolidinediones，can also improve the psoriasis skin lesion symptoms by changing the hypodermic chronic inflammatory state while treating the type 2 diabetes mellitus. Therefore，this paper summarizes the relevant research progress，analyzes the possible pathophysiological mechanisms，and related therapies for these two diseases.